The goal of the Pennsylvania Black Fly Suppression Program is to reduce adult black fly populations to tolerable levels during the spring and summer recreational seasons using environmentally compatible methods. The program involves the monitoring and treatment of many rivers and streams across Pennsylvania. DEP biologists and student interns conduct black fly monitoring, laboratory identification of samples, data entry, treatment operations and management of aerial spray contracts. Treatments are done by helicopter, using Bacillus thuringiensis israelensis (Bti), a naturally occurring soil bacterium, to selectively target four of the black fly species in the Simulium jenningsi species group that bother people. More than three million Pennsylvania residents benefit from this program annually. The program provides relief from adult black flies so residents and tourists can fully enjoy outdoor recreational activities in Pennsylvania. For more information on the Black Fly Suppression Program in Pennsylvania, please visit
Pennsylvania's Black Fly Suppression Program web site.
West Nile Virus
The goal of Pennsylvania's West Nile Virus Control Program is to combat the spread of West Nile virus, which is transmitted by mosquitoes. In order to accomplish this goal, a comprehensive network covering all 67 counties in the commonwealth was created. This network, consisting of state, regional and county personnel, conducts mosquito surveillance and dead bird collections, and monitors for the occurrence of West Nile virus in horses and humans. Mosquito control activities are implemented as required. For more information on the West Nile Virus Control Program in Pennsylvania, please visit
Pennsylvania's West Nile Virus Control Program web site.